Nutrient-enriched formula versus standard term formula for preterm infants following hospital discharge

Preterm infants are often growth-restricted at hospital discharge. Feeding infants after hospital discharge with nutrient-enriched formula rather than standard term formula might facilitate "catch-up" growth and improve development.

To determine the effect of feeding nutrient-enriched formula compared with standard term formula on growth and development for preterm infants following hospital discharge.

We used the standard search strategy of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2011, Issue 4), MEDLINE, EMBASE, and CINAHL (to September 2011), conference proceedings and previous reviews.

Randomised or quasi-randomised controlled trials that compared the effect of feeding preterm infants following hospital discharge with nutrient-enriched formula (post-discharge formula or preterm formula) compared with standard term formula.

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors.

We found 15 eligible trials in which a total of 1128 preterm infants participated. The trials were of variable methodological quality with lack of allocation concealment and incomplete follow-up in some trials being the major potential sources of bias. The trials (N = 10) that compared feeding infants with "post-discharge formula" (energy density about 74 kcal/100 ml) versus standard term formula (about 67 kcal/100 ml) did not find consistent evidence of effects on growth parameters up to 12 to 18 months corrected age. The trials (N = 5) that compared feeding with "preterm formula" (about 80 kcal/100 ml) versus term formula found some evidence of higher rates of growth through infancy: weighted mean differences at 12 to 18 months corrected age about 500 g in weight, 5 to10 mm in length, and 5 mm in head circumference. Few trials assessed neurodevelopmental outcomes and these did not detect any statistically significant differences in developmental indices at 18 months corrected age. There are not yet any data on growth or development through later childhood.

Current recommendations to prescribe "post-discharge formula" for preterm infants following hospital discharge are not supported by the available evidence. Some limited evidence exists that feeding preterm infants following hospital discharge with "preterm formula" (which is generally only available for in-hospital use) may increase growth rates up to 18 months corrected age.